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Purpose: To determine the variation of OXIS contact areas in primary molars using digital impressions generated from an intraoral scanner (IOS). Methods: A cross-sectional study was carried out on 214 caries-free posterior quadrants of 80 children (38 males and 42 females) aged 3–6 years. Calibration of taking digital impressions with the IOS procedure was performed initially through scanning of ten quadrants of children to provide a learning environment to the examiner. The digital impressions were then exported, and the type of interproximal contact areas present between the distal surface of the primary first molar and the mesial surface of the primary second molar were identified according to the OXIS classification. The prevalence of the types of OXIS contact areas was expressed in the form of numbers and percentages. The chi-square test was applied to investigate the variability among the arches and to understand the association of OXIS contact areas across age, gender, and arches. Results: The most common contact area type observed was I-type (59.8%), followed by S-type (15.4%), X-type (12.6%), and O-type (12.2%). The I-type contact area was most frequently seen in both males (51.6%) and females (65.5%), while the S-type contact area in males (14.7%) and X-type contact area in females (8.4% each) were the least frequent with no statistical significance between genders (p > 0.05). All three age groups studied showed the highest prevalence of the I-type contact area, which increased with an increase in age (p < 0.05). The inter-arch comparison showed a significant result in terms of the X-type contact area on the right side, and O-type, X-type, and I-type contact areas on the left side, while no statistical difference was seen in the intra-arch comparison for all contact types. Conclusion: I-type contact areas were the most prevalent across the arches, age groups and genders. [ABSTRACT FROM AUTHOR]

Aim: The present clinical study aimed to assess the efficacy of conventional versus cordless displacement systems on gingival retraction for use with an intra-oral scanner and changes in periodontal indices. Materials and Methods: A total of 20 participants were selected for a split-mouth study (20 sites – Group Sc, 20 sites – Group Es). The outcomes were measured at day 0, day 1, and day 7 of follow-up in terms of Immediate horizontal displacement, Plaque Index, and Bleeding Index. Unpaired and Paired t-test was used as the parametric tests and statistical analysis was performed. Results: A statistically significant change was observed in terms of BI on day 0, but no statistically significant change was observed for either group in terms of IHD and PI. Conclusion: The cordless material caused the least trauma to gingival tissue and was more compatible with intra-oral scanning devices.

Background: In this study, we aimed to compare the effects of conventional and digital impressions on several parameters (inter-implant distance, intra-implant distance, inter-implant axis, and intra-implant axis) of three implants in curved lines and straight lines by using a laboratory scanner (LBS) versus an intra-oral scanner (IOS). Methods: Two 3D models were fabricated using a printer, each model with three internal hex implants analogues at the positions of 15#,16#,17# (straight line) and 12#,13#,14# (curved line). Standard intra-oral scan bodies (ISBs) were used, and the two models were scanned using 7 Series dental wings (LBS, reference model), followed by ten scans with Primescan (digital method). Standard Tessellation Language (STL) files were created. Five polyether impressions were taken from each model (straight and curved), and gypsum type 4 models were poured; each model was scanned five times to create a total of 25 STL files for each group (conventional method). The comparison between all the STL files (conventional and digital) was made by superimposition of the STL files on the STL reference model laboratory file using a 3D analyzing software. A Kolmogorov–Smirnov test was performed, followed by Mann–Whitney tests and Wilcoxon signed-rank tests. (p < 0.05). Results: For the conventional method, the mean errors were significantly higher for the curved line model (12–14) compared to the straight line model (15–17) for most parameters (p < 0.05). For the digital method, the mean errors were significantly higher for the curved-line model (12–14) compared to the straight line model (15–17) in half of the parameters (p < 0.05). Within the curved line model (12–14) and the straight line model (15–17), the mean errors between the conventional method and the digital method were not significant for most variables. Conclusions: The difference between curved lines and straight lines has an impact on the mean error of the conventional method. Both methods are reliable for straight and curved lines in partially dentate situations. [ABSTRACT FROM AUTHOR]

The main objective of this study is to develop a handheld dental optical coherence tomography (OCT) system capable of imaging the target area of the teeth in the oral cavity and demonstrate the applicability of the developed system to in vivo dental disease diagnosis based on a user‐friendly scanner form. The design of the developed system is based on mimicking the shape of a commonly used commercial intra‐oral scanner (IOS) so that the system users do not feel awkward when using it. A microelectromechanical system (MEMS) scanning unit was used to optimize the overall size of the system, and the optical axis was designed in a Z‐shape to maximize the beam size reflected by the MEMS mirror. A pre‐study of in vivo oral scanning was performed to demonstrate the enhanced clinical feasibility of the developed system. Furthermore, the main experiment classified teeth with worn cervical regions into two groups according to the cervical abrasion shape. The developed dental OCT system produced a three‐dimensional image of the scanning area and quantitatively analyzed the margin gap through an A‐scan profile based on cross‐sectional images. This study confirms the effectiveness of the developed handheld dental OCT system in actual dental clinical practice, and we expect our system to be utilized for various dental diseases, not only for diagnosing a cervical abrasions. [ABSTRACT FROM AUTHOR]

Background: The purpose of this in vitro study was to compare the inter-implant distance, inter-implant axis, and intra-implant axis of three implants in a straight line by using a laboratory scanner (LBS) versus an intra-oral scanner (IOS) with two different intra-oral scan bodies (ISBs). Methods: A 3D model was printed with internal hex implant analogs of three implants in positions 15#, 16#, and 17#. Two standard intra-oral scan bodies (ISBs) were used: MIS ISB (two-piece titanium) and Zirkonzhan ISB (two-piece titanium). Both ISBs were scanned using 7 Series dental wings (LBS) and 30 times using Primescan (IOS). For each scan, a stereolithography (STL) file was created and a comparison between all the scans was performed through superimposition of the STL files by using 3D analysis software (PolyWorks® 2020; InnovMetric, Québec, QC, Canada). A Kolmogorov–Smirnov test was performed followed by a Mann–Whitney test (p < 0.05). Results: The change in inter-implant distance for the MIS ISB was significantly lower compared to the ZZ (p < 0.05). The change in intra-implant angle was significantly lower for the ZZ ISB compared to MIS (p < 0.05). The changes in inter-implant angle between the mesial and middle and between the middle and distal were significantly lower for MIS compared to ZZ in contrast to mesial to distal, which was significantly higher (p < 0.05). Conclusions: Both ISBs showed differences in all the parameters between the LBS and the IOS. The geometry of the scan abutment had an impact on the inter-implant distance as the changes in the inter-implant distance were significantly lower for the MIS ISB. The changes in the intra-implant angle were significantly lower for the ZZ ISB. There is a need for further research examining the influence of geometry, material, and scan abutment parts on the trueness. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this systematic review was to compare the clinical performance of lithium disilicate (LDS) and zirconia (Z) single crowns manufactured by computer-aided design/computer-aided manufacturing (CAD/CAM) systems using intraoral optical scanners (IOS). Materials and methods: An electronic search for articles published between January 2012 and January 2022 in the English language was performed with the Medline/Pubmed database under the guidelines of Preferred Reporting Items for Systemic Reviews and Meta-analysis (PRISMA). The specific search terms used were "zirconia", "lithium disilicate", "CAD/CAM", "intraoral optical scanner", and "survival". Results: The initial electronic search resulted in 278 articles. Most of the resulting articles were excluded, six clinical studies addressing the clinical outcomes of Z and LDS crowns fitted the inclusion criteria and were selected for review. Of these six studies, three were randomised controlled trials, two were retrospective studies, and one was a prospective study. To quantify the clinical performance of the crowns several parameters were recorded, including fractures, endodontic complications, periodontal complications, technical complications, aesthetic complications, and biological complications. It was noted that the most common technical complication of Z and LDS crowns was chipping at a rate of 1.4% and 5% respectively. Regarding Z crowns, aesthetic concerns were the most frequently observed complication. Conclusion: The outcomes of this systematic review indicate that Z and LDS crowns display a similar incidence of periodontal and endodontic complications when compared to metal-ceramic crowns, suggesting that these all-ceramic materials are viable alternatives. The incidence of chipping was higher in LDS crowns compared to other materials, while Z crowns were inferior in terms of aesthetics. [ABSTRACT FROM AUTHOR]

By utilising open-source digital software, clinicians can create an integrative digital workflow composed of various technological systems. This report presents a clinical case that follows a comprehensive digital workflow to improve the smile of a 42-year-old female patient. The patient presented with minor attrition of maxillary anterior teeth and discoloured, asymmetrical composite restorations on central maxillary incisors. Her smile was rehabilitated by restoring her maxillary anterior teeth with lithium disilicate ceramic veneers. A smile design system was used to create a virtual simulation of the patient's desired treatment outcome. Utilising a 3D tooth library generated by the smile design system, extra-oral photographs, and intra-oral scans of the patient's maxillary and mandibular arches, a 3D model of the proposed smile design was created in an advanced 3D sculpting software. The resin casts that were fabricated with a 3D printer were used to fabricate a mockup and sent to the laboratory as reference for the final restoration. The specific shade recipe for the ceramic veneers was obtained using a special polar eye filter and digital shade matching software. There is no doubt that advancements in digital technology are providing clinicians with limitless treatment modalities. From intra-oral scanners and smile design systems to 3D sculpting software and even digital shade matching systems, continuous technological developments are paving the way for the complete digitalisation of dentistry. This case report presents an example of this digital revolution. [ABSTRACT FROM AUTHOR]

Introduction: To evaluate the shade matching of teeth restored with OMNICHROMA using four different teeth shade-selection techniques. Methods: Thirty sound upper first premolar teeth were used. Shade was taken by the VITA Linearguide 3D-MASTER, the VITA Easyshade V, digital photography, and the TRIOS 3 intraoral scanner for the cervical area. Subsequently, a Class V cavity was prepared and filled with an OMNICHROMA filling, and another reading for the shade was taken. Results: Value of ΔE in all groups were significantly higher than the clinically acceptable value (ΔE: 3.7) (P < 0.001). One-way ANOVA measurements showed statistically significant differences among the groups (P < 0.001). Conclusion: OMNICHROMA composite showed some degree of mismatch with the surrounding tooth structure. This in vitro model could not simulate complex oral situation and more clinical studies are necessary.

Introduction: To evaluate the shade matching of teeth restored with OMNICHROMA using four different teeth shade-selection techniques. Methods: Thirty sound upper first premolar teeth were used. Shade was taken by the VITA Linearguide 3D-MASTER, the VITA Easyshade V, digital photography, and the TRIOS 3 intraoral scanner for the cervical area. Subsequently, a Class V cavity was prepared and filled with an OMNICHROMA filling, and another reading for the shade was taken. Results: Value of ΔE in all groups were significantly higher than the clinically acceptable value (ΔE: 3.7) (P < 0.001). One-way ANOVA measurements showed statistically significant differences among the groups (P < 0.001). Conclusion: OMNICHROMA composite showed some degree of mismatch with the surrounding tooth structure. This in vitro model could not simulate complex oral situation and more clinical studies are necessary. [ABSTRACT FROM AUTHOR]

Objectives: This study aims to explore the effect of improving clinical efficiency by replacing traditional impression workflow with centralized digital impression workflow., Methods: The department of prosthodontics in Center of Stomatology, Peking University Shenzhen Hospital has improved the clinical workflow by replacing the traditional impression made by doctors using impression materials for each patient with a centralized digital impression made by one technician for all patients in the department. This cross-sectional study recorded the chairside time required for impression taking in patients undergoing single posterior zirconia full crown restoration before clinical process improvement; the time required for centralized digital impression production; the comfort level of patients; and the adjacency relationship, occlusal contact relationship, and time required for prostheses adjusting (i.e., whether centralized digital impressions would compromise the quality of pro-stheses and increase the time of prostheses adjusting)., Results: The average time to make a traditional impression was (9.98±1.41) min, and the average time required for each patient to make a centralized digital impression was (5.98±1.49) min, which was shorter than that to used make a traditional impression ( P <0.05). Centralized digital impression made patients feel more comfortable compared with traditional impression ( P <0.05). The adjacency relationship of restorations by centralized digital impression was more appropriate ( P <0.05), and no significant difference in occlusal relationship was found ( P >0.05). The time required for adjusting prostheses also had no significant differences ( P >0.05)., Conclusions: Centralized digital impression can improve clinical efficiency for patients undergoing single posterior zirconia crown restoration. The time for impression taking is shorter, and patients feel more comfortable without compromising the quality of the prostheses.

Background: The purpose of this in vitro study was to compare the implant axis' spatial position and orientation by using laboratory scanner versus intra-oral scanner with three different scan abutments. Methods: A 3D model was printed with an internal hex implant analog in the place of teeth 35#. Three standard scan abutments were used: MIS (two-piece titanium), AB (two-piece PEEK and titanium base) and ZZ (one-piece PEEK). Each scan abutment was scanned 30 times by TRIOS E3 (laboratory scanner) and 30 times by Omnicam (intra-oral scanner). For each scan, an STL (stereolithography) file was created, and the spatial characterization of each scan abutment was measured in the X, Y, Z coordinates, and rotational and longitudinal angles. The comparison between all the scans was conducted by superimposition of the STL files, using a 3D software. A t-test and Wilcoxon signed-rank test were used. (p < 0.05) Results: Only the MIS scan abutment showed no statistical difference in the X and Z axes. (p < 0.05). All other scan abutments showed a statistical difference in all axes. The rotational angle of the AB scan abutment was twice the angle of the MIS and ZZ scan abutments. Conclusions: All three scan abutments showed a rotational deviation of the implant axis between the laboratory scanner and the intra-oral scanner. The AB scan abutment showed the greatest deviation (1.04 degrees) while the other two abutments showed deviations of about half a degree in relation to the laboratory scan abutment. There is a need for further studies which will examine the influence of geometry, material, and scan abutment parts on the accuracy of the scan obtained. [ABSTRACT FROM AUTHOR]

Background: The purpose of this in vitro study was to compare the implant axis’ spatial position and orientation by using laboratory scanner versus intra-oral scanner with three different scan abutments. Methods: A 3D model was printed with an internal hex implant analog in the place of teeth 35#. Three standard scan abutments were used: MIS (two-piece titanium), AB (two-piece PEEK and titanium base) and ZZ (one-piece PEEK). Each scan abutment was scanned 30 times by TRIOS E3 (laboratory scanner) and 30 times by Omnicam (intra-oral scanner). For each scan, an STL (stereolithography) file was created, and the spatial characterization of each scan abutment was measured in the X, Y, Z coordinates, and rotational and longitudinal angles. The comparison between all the scans was conducted by superimposition of the STL files, using a 3D software. A t-test and Wilcoxon signed-rank test were used. (p < 0.05) Results: Only the MIS scan abutment showed no statistical difference in the X and Z axes. (p < 0.05). All other scan abutments showed a statistical difference in all axes. The rotational angle of the AB scan abutment was twice the angle of the MIS and ZZ scan abutments. Conclusions: All three scan abutments showed a rotational deviation of the implant axis between the laboratory scanner and the intra-oral scanner. The AB scan abutment showed the greatest deviation (1.04 degrees) while the other two abutments showed deviations of about half a degree in relation to the laboratory scan abutment. There is a need for further studies which will examine the influence of geometry, material, and scan abutment parts on the accuracy of the scan obtained.

Aim: The aim of this in vitro study was to investigate the influence of scan paths on the accuracy (trueness and precision) of intra-oral scanning of an implant impression on an edentulous patient., Material and Methods: An epoxy resin maxillary model was made with 6 bone level implants (NobelParallel Conical Connection RP, NobelBiocare®). The implants were placed at the spot of the first incisor, the canine and the first molar. The trans gingival component (Multi-unit, NobelBiocare®) was screwed onto the implants. The scanbodies (IO 2C-A, Elos Accurate®) were then screwed onto the multi-units. The model was run through a coordinate measurement machine to obtain a control cast. Then, five different scanning paths, respectively the zigzag technique (ZZT), the zigzag technique with palatal (ZZTP), the wrap technique (WT), the wrap technique with palatal (WTP), and the big zigzag technique (BZZT), were applied by a single operator. Finally, each scan was compared to the control model. Results were assessed by one-way ANOVA and linear mixed effects models at P<0.05., Results: The study showed that scan paths ZZT and ZZTP had significantly lower absolute positioning errors and residual mean square errors than the others (P<0.0001). For distances between consecutive implant axes and for absolute vertical errors, their superiority was borderline (P<0.10). Overall, techniques ZZT and ZZTP were equally performant and proved to be the most accurate., Conclusions: This in vitro experimental study demonstrates that the scan path can have an influence on the accuracy of the optical impression for full arch rehabilitation on implants.

Our goal is to introduce in the training of students and the post-graduate students in orthodontics studying and working with digital technologies to generate virtual "plaster" models and work with digital X-rays. For this purpose, we evaluate the volume of gypsum models created by students and residents for two years of their training and create a list of positives and shortcomings in introducing the full digital use and storing of the biometric data of patients. The study included 661 patients treated by post-graduate and the students in the FDM – Sofia, for the last two school years. In total, in the course of two school years the treatment of patients from students and post-graduate ones is stored 1474 plaster models, for which the materials are consumed and considerable time and human labor. If all these models are digitally scanned and stored as files, they will not occupy space and will turn off the work of the dental technicians. For the accuracy of the plaster models there are several compromising points – used materials and human factor. The implementation of intraoral and facial scanners and the good processing of their data certainly affect the effectiveness, accuracy and predictability of the results of orthodontic treatment. When establishing database of digital models, a model for diagnosis at any time during the training and testing may be provided to learners at random. Electronically the stored dossiers can provide data, both for biometric analyses and for radiological analyses, which can be combined with the photographic image of the patient. In this way, the practical-diagnostic exercises of graduate and university students will be facilitated, and the examination by the lecturers will be facilitated. [ABSTRACT FROM AUTHOR]

Objectives: Tooth colour determination is an essential component in the preservative and prosthetic workflow during production of tooth-coloured restorations. The aim of the study was to compare the clinical suitability of conventional, visual tooth colour determination and digital methods. Materials and methods: Tooth colour of vital, natural central incisors among a total of 107 subjects was determined visually by a dentist (VD) and dental technician (VDT) using VITA Toothguide 3D-MASTER®, digitally by the spectrophotometer VITA Easyshade Advance 4.0 (reference instrument) and Trios®Color intra-oral scanner (test subject). Reliability was examined by repeating the digital measurements of 20 teeth three times. The analysis was based on the recorded 3D-MASTER values and L* a* b/ L* C* h parameters. Results: The measuring accuracy was 43.9% with the Trios®Color scanner, 35.5% for VD and 34.6% for VDT. In 25.5% of cases, the scanner's results corresponded with VD and in 33.6% with VDT. The visual methods corresponded with 45.8%. All mean values of the recorded colour differences fell within the clinically acceptable range of Δ E ≤ 6.8. The intra-oral scanner attained repeatability of 78.3% and the VITA Easyshade system of 76.6%. Conclusions: The Trios®Color intra-oral scanner appears to be a good alternative to the current standard of visual tooth colour determination. The new module attains better results than the visual method and is comparable to the reference instrument. Clinical relevance: Dentistry becomes increasingly digitalized and tooth colour determination devices have generally to be improved. Therefore, the investigation of a new digital device is important for future developments. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate the marginal and internal adaptation of monolithic zirconia restoration made without physical model by digital intraoral scanner. Materials and methods: A prospective clinical trial was performed on 11 restorations as a pilot study. The monolithic zirconia restorations were fabricated after digital intraoral impression taking by intraoral scanner (TRIOS, 3shape, Copenhagen, Denmark), computer-aided designing, and milling manufacturing process. Completed zirconia crowns were tried in the patients' mouth and a replica technique was used to acquire the crown-abutment replica. The absolute marginal discrepancy, marginal gap, and internal gap of axial, line angle, and occlusal part were measured after sectioning the replica in the mesiodistal and buccolingual direction. Statistical analysis was performed using Kruskal-Wallis and Mann-Whitney U test (α=.05). Results: From the adaptation analysis by replica, the statistically significant difference was not found between mesiodistal and buccolingual sections (P>.05), but there was significant difference among the measurement location (P<.01). The amount of absolute marginal discrepancy was larger than those of marginal gap and internal gap (P<.01). Conclusion: Within the limitations of this study, the adaptation accuracy of model-free monolithic zirconia restoration fabricated by intraoral scanner exhibited clinically acceptable result. However, the margin of zirconia crown showed tendency of overcontour and cautious clinical application and follow up is necessary. [ABSTRACT FROM AUTHOR]

The objective of this work was to propose an automated and direct process to grade tooth wear intra-orally. Eight extracted teeth were etched with acid for different times to produce wear and scanned with an intra-oral optical scanner. Computer vision algorithms were used for alignment and comparison among models. Wear volume was estimated and visual scoring was achieved to determine reliability. Results demonstrated that it is possible to directly detect submillimeter differences in teeth surfaces with an automated method with results similar to those obtained by direct visual inspection. The investigated method proved to be reliable for comparison of measurements over time. [ABSTRACT FROM AUTHOR]

Introduction The current gold standard is a conventional impression made with various impression materials and trays and results in a gypsum cast. With the development of milling and printing materials in dentistry, especially zirconia, a digital model has become increasingly important. Objectives To compare the accuracy of the conventional impression scan (CIS), gypsum cast scan (GCS), and digital impression scan (DIS) to obtain a full-arch digital model. Materials and methods A resin reference cast was fabricated. It was scanned by an extra-oral scanner to measure its accuracy as a reference scanner. Eight conventional impressions of the reference cast were taken by polyvinyl siloxane and scanned. After that, they were poured with type IV dental stones and scanned too. The reference cast was scanned by an intraoral scanner eight separate times. Digital models within each group were superimposed individually to measure precision. In addition, each model from each group was superimposed on one model from the reference scanner precision group to measure trueness. Results The reference scanner showed the highest accuracy among groups with a precision of 1.5±0.8 µm and a trueness of 5.5±1.9 µm (P<0.006), while precision values of gypsum cast were 8.1±1.7 µm and trueness values were 9.3±2.6 µm (P<0.012). Conventional impressions showed a precision of 14.06±2.01 µm and a trueness of 16.15±2.07 µm (P<0.012). Digital impressions were the least accurate among the groups, as precision values were 38.22±15.23 μm and trueness values were 35.19±8.7 μm (P<0.006). Conclusion The gypsum cast scans showed the highest accuracy, followed by the conventional impression scans, and finally the digital impression scans, with no clinical significance., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2022, Husein et al.)

Introduction: Digital impressions in implant dentistry rely on many variables, and their accuracy, particularly in complete edentulous patients, is not well understood. Aim. The purpose of this literature review was to determine which factors may influence the accuracy of digital impressions in implant dentistry. Emphasized attention was given to the design of the intra-oral scan body (ISB) and scanning techniques., Materials and Methods: A Medline, PubMed and EBSCO Host databases search, complemented by a hand search, was performed in order to select relevant reports regarding the appliance of digital impressions in implant dentistry. The search subject included but was not limited to accuracy of digital impressions in implant dentistry, digital scanning techniques, the design and material of the ISBs, and the depth and angulation of the implant. The related titles and abstracts were screened, and the remaining articles that fulfilled the inclusion criteria were selected for full-text readings., Results: The literature search conducted for this review initially resulted in 108 articles, among which only 21 articles fulfilled the criteria for inclusion. Studies were evaluated according to five subjects: accuracy of digital impressions in implant dentistry; the design and material of the intra-oral scan bodies; scanning technique; the influence of implants depth/angulations on the digital impression and accuracy of different intra-oral scanner devices., Conclusions: The accuracy of digital impressions in implant dentistry depends on several aspects. The depth/angulation of the implant, the experience of the operator, the intra-oral scanner used, and environmental conditions may influence the accuracy of digital impressions in implant dentistry. However, it seems that ISBs' design and material, as well as scanning technique, have a major impact on the trueness and precision of digital impressions in implant dentistry. Future research is suggested for the better understanding of this subject, focusing on the optimization of the ISB design and scanning protocols.